<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script>
        var a = 1;
        var b = 1;
        //前置递增用法
        console.log(++a);  
        console.log(a);
        
        //后置递增用法
        console.log(b++); 
        console.log(b);
    </script>
</head>
<body>
    
</body>
</html>